Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
Fig. 1 is the process flow diagram of the measuring method embodiment one of aerogenerator low voltage ride-through capability of the present invention, and as shown in the figure, present embodiment specifically comprises the steps:
Step 101, to aerogenerator and site input less than the measuring voltage of standard voltage value;
Because test is the low voltage ride-through capability of aerogenerator, so the measuring voltage of importing in the also site of aerogenerator is necessarily less than the aerogenerator standard voltage value;
Step 102 is measured the maintenance of aerogenerator till from input test voltage to the aerogenerator off-grid and is incorporated into the power networks the time;
Because low voltage ride-through capability has requirement, be exactly under different test voltages, the time of being incorporated into the power networks that aerogenerator needs is different;
Step 103; if keep the time of being incorporated into the power networks less than the default threshold values time; then adjust the switching time of crow bar holding circuit of aerogenerator and/or the bypass resistance value of crow bar holding circuit, and the under-voltage protection definite value of aerogenerator, make to keep being incorporated into the power networks the time more than or equal to the threshold values time.
Time has surpassed or has equaled the threshold values time if keep being incorporated into the power networks; then do not need the switching time of the crow bar holding circuit of aerogenerator and the bypass resistance value of crow bar holding circuit are adjusted; just when keeping the time of being incorporated into the power networks less than the default threshold values time; need adjust; purpose is to make to keep being incorporated into the power networks the time more than or equal to the threshold values time; so just make the low voltage ride-through capability of aerogenerator reach requirement; thereby off-grid at once not when line voltage falls is protected electrical network.
Fig. 2 is the process flow diagram of the measuring method embodiment two of aerogenerator low voltage ride-through capability of the present invention, and as shown in the figure, present embodiment specifically comprises the steps:
Step 201 is set up the electric system Equivalent Model of aerogenerator, transformer, circuit, load and network topology structure, builds the energy measurement computing platform;
Can utilize the actual electric network data, in the digsilent software emulation platform, set up the electric system Equivalent Model of aerogenerator, transformer, circuit, load and network topology structure etc., build the computing platform that can realize low voltage ride-through capability emulation.
Table 1 is the concrete parameter list of aerogenerator
Table 2 is the concrete parameter list of circuit:
Model |
Rated current (KA) |
Resistance (ohm/km) |
Reactance (ohm/km) |
Susceptance (uS/km) |
LGJ-150 |
0.294 |
0.21 |
0.4 |
1.3 |
2*LGJ-240 |
1.22 |
0.066 |
0.3493 |
|
LGJ-400 |
0.845 |
0.07988 |
0.4076 |
1.41 |
2*LGJ-400 |
1.69 |
0.03954 |
0.2996 |
1.889 |
Table 3 is the concrete parameter list of transformer:
The 110kV network transformer
The 35kV network transformer
Load parameter is exactly burden with power and load or burden without work, or impedance and reactance.
Step 202 is selected the node aerogenerator of voltage fluctuation greater than predeterminated voltage fluctuation threshold values;
Specifically be exactly that the dynamic response value when obtaining each bar circuit and each bar bus place and respectively three-phase shortcircuit taking place is selected the node aerogenerator of voltage fluctuation greater than predeterminated voltage fluctuation threshold values;
In the under-voltage protection of the low voltage ride-through capability of not considering blower fan, blower fan self with send route protection; obtain system dynamics response (being exactly magnitude of voltage, current value and active power and reactive power) when each bar circuit and each bar bus place respectively three phase short circuit fault take place in the system; observe the voltage stability of main monitoring node, filter out the aerogenerator node that must carry out the low-voltage capabilities setting.
The purpose of this step just is meant to search removes the node aerogenerator that needs to possess low voltage ride-through capability, because some engine is in some node, in any case short trouble is set, system voltage and stability change are very little, so aerogenerator does not just need to have possessed low voltage ride-through capability.
Step 203, the also site input of the aerogenerator in the electric system Equivalent Model of described network topology structure is less than the measuring voltage of standard voltage value;
Fig. 3 is the circuit diagram of double-fed induction wind driven generator, and as shown in the figure, the stator side of aerogenerator directly connects electrical network, and rotor-side connects electrical network by frequency converter.Principal feature is that rotor top-cross orthogonal transducer only needs 25% blower fan rated power; The trend that flows through current transformer has two kinds of possibility directions.Crow bar protection (crowbar) circuit wherein is in the double-fed induction wind driven generator rotor-side crowbar circuit to be housed; for the rotor-side circuit provides bypass; when detecting the network system fault and electric voltage dropping occurs; locking double-fed induction wind driven generator exciter converter; the bypass in input rotor loop simultaneously (releasing energy resistance) protective device; reach the electric current and the superpotential effect of rotor-side transducer of restricted passage exciter converter; keep not off-grid operation of aerogenerator (this moment double-fed induction send out aerogenerator move) with this, and net side frequency converter is connected with the transformer continuation by the induction motor mode.
Based on crow bar protection switching opportunity in the protection of the crow bar of aerogenerator; when promptly arriving electric current sill value (for example 1.5 to 2 times load current value); ability switching when the stand-by period is 0-10ms; the bypass circuit resistance value; be the key parameter such as resistance value of crowbar holding circuit and the typical value of protection definite value, assess each wind-powered electricity generation machine ride-through capability and whether satisfy the low voltage ride-through capability requirement.
Step 204 is measured the maintenance of described aerogenerator till from input test voltage to described aerogenerator off-grid and is incorporated into the power networks the time;
Fig. 4 is in the measuring method of aerogenerator low voltage ride-through capability of the present invention, low voltage ride-through capability requires synoptic diagram, as shown in the figure, ordinate is ratio aerogenerator and the actual measurement voltage of site and load voltage value, horizontal ordinate is the default threshold values time, curve is exactly that aerogenerator need keep the threshold values of the time of being incorporated into the power networks under some ratios of actual measurement voltage and load voltage value among the figure, for example:
When the wind-powered electricity generation unit in the wind energy turbine set has when the point voltage that is incorporated into the power networks falls to 20% rated voltage, can keep the low voltage ride-through capability of the time of being incorporated into the power networks for operation 625ms;
In the wind-powered electricity generation machine is incorporated into the power networks the 3s of point voltage after falling, can return to rated voltage 90% the time, the wind-powered electricity generation unit in the wind energy turbine set keeps being incorporated into the power networks.
Whether step 205 judge keeps the time of being incorporated into the power networks less than the default threshold values time, if execution in step 206 then, otherwise execution in step 207;
If keep the time of being incorporated into the power networks to be greater than or equal to the default threshold values time, illustrate that then aerogenerator meets the requirement as the curve among Fig. 4, the result of test point is below curve, the low voltage ride-through capability that aerogenerator is described is up to standard, if and maintenance is incorporated into the power networks the time less than the default threshold values time, illustrate that then aerogenerator does not meet the requirement as the curve among Fig. 4, above curve, illustrate that the low voltage ride-through capability of aerogenerator is not up to standard;
Step 206, the switching time of the crow bar holding circuit of adjustment aerogenerator and/or the bypass resistance value of crow bar holding circuit, and the under-voltage protection definite value of aerogenerator, execution in step 203;
Change the switching time of crow bar holding circuit and/or the bypass resistance value of crow bar holding circuit, can change the low voltage ride-through capability of aerogenerator like this, carry out 203 once more and test, up to the requirement that meets as the low voltage ride-through capability among Fig. 4;
The switching time can be from the 0-10 millisecond, and the bypass resistance value is the 0-1 per unit value.
Step 207 generates measurement report.
Test report has two kinds; a kind of is test time to judge directly that in step 205 meeting low-voltage passes through under the situation of requirement; comprise measuring voltage each time in the test report that generates; maintenance under this measuring voltage is incorporated into the power networks the time; and the bypass resistance value of the switching time of the crow bar holding circuit of aerogenerator and crow bar holding circuit; and the under-voltage protection definite value of aerogenerator, and the result is that aerogenerator meets low-voltage and passes through requirement.
Another kind is to judge directly that in step 205 not meeting low-voltage passes through requirement; the bypass resistance value of having revised switching time of crow bar holding circuit and/or crow bar holding circuit once or met low-voltage for several times and pass through requirement; measuring voltage when the test report of this moment has comprised test each time; maintenance under this measuring voltage is incorporated into the power networks the time; and the bypass resistance value of the switching time of the crow bar holding circuit of aerogenerator and crow bar holding circuit; end product is under the situation of the bypass resistance value of the switching time of the crow bar holding circuit of which aerogenerator and crow bar holding circuit, and aerogenerator low-voltage up to specification is passed through requirement.
Thus; utilize the measuring method of aerogenerator low voltage ride-through capability of the present invention; can be so that aerogenerator be selected the switching time of suitable crow bar holding circuit and the bypass resistance value of crow bar holding circuit; and the under-voltage protection definite value of aerogenerator; make aerogenerator low-voltage up to specification pass through requirement; thereby make when line voltage falls not off-grid at once of aerogenerator, electrical network is protected.
Fig. 5 is the process flow diagram of the measuring method embodiment three of aerogenerator low voltage ride-through capability of the present invention, and as shown in the figure, present embodiment specifically comprises the steps:
Step 301 is set up wind energy turbine set realistic model shown in Figure 6 on the DigSILENT emulation platform, choose aerogenerator, transformer, circuit, wind energy turbine set model parameter;
Node A among Fig. 6 is that highest level has A1 and two nodes of A2, and the rank of B node is taken second place, and has two of B1 and B2, and the rank of C node is more taken second place, and the D node is minimum node.
Step 302; on the DigSILENT emulation platform, system shown in Figure 6 is carried out big perturbation analysis; during emulation in the taking into account system each circuit and each bus place three phase short circuit fault takes place respectively; research is in the under-voltage protection of the low voltage ride-through capability of not considering blower fan, blower fan self and send the dynamic response of system under the route protection situation; observe the voltage stability of main monitoring point, filter out the node aerogenerator that must carry out the low-voltage capabilities setting.
Simulation study find not consider blower fan low voltage ride-through capability, blower fan self under-voltage protection and send under the route protection situation, system either machine off-grid on a large scale under the GPF (General Protection False action threatens to the security and stability of electrical network.Therefore, for improving the security and stability of electrical network under failure condition, require wind energy turbine set will have certain low voltage ride-through capability.
Step 303; the design of low voltage ride-through capability of wind turbine generator system optimal control policy: take all factors into consideration in the blower fan crow bar protection crow bar protection switching opportunity; the bypass circuit resistance value; and the under-voltage protection definite value of aerogenerator, assess each wind-powered electricity generation machine ride-through capability and whether satisfy relevant the low voltage ride-through capability requirement.For the blower fan that meets the demands, write wind-electricity integration LVRT capability study report, provide the setting of the key parameter that satisfies the blower fan low voltage ride-through capability or suggestion is set; If do not satisfy the LVRT control strategy searching process that changes next step over to.
Step 304; proceed the design of low voltage ride-through capability of wind turbine generator system optimal control policy for the blower fan that does not satisfy the LVRT ability in the previous step process; the span of key parameter and protection definite value in the protection configuration of revision wind energy turbine set circuit and the protection of blower fan crow bar; change the major parameter relevant with low voltage ride-through capability; and carry out contrast simulation, till the low voltage ride-through capability of blower fan can meet the demands.
The requirement of the low voltage ride-through capability of blower fan is based on crow bar holding circuit setting low-voltage and passes through control strategy, and the requirement of blower fan low voltage ride-through capability.
Step 305; the electrical network wind energy turbine set part blower fan of initial system shown in Figure 6 does not have the LVRT ability, and the wind-powered electricity generation unit is after fault takes place, and cutter and electrical network break away under the effect of GPF (General Protection False; the voltage stability of system side and frequency stability descend, and cause other synchrodyne collapse of voltages.
When being applied to wind-powered electricity generation net wind energy turbine set shown in Figure 6 according to the selected wind-powered electricity generation unit LVRT control strategy of above step, to under the same fault situation, wind-powered electricity generation field energy with LVRT ability keeps not off-grid operation between age at failure, provide the voltage support to system side, and can behind failure removal, enter the steady-state operation state fast, guaranteed the stable operation of system.
The analytic system of aerogenerator low voltage ride-through capability of the present invention specifically comprises: input block, be used for to described aerogenerator and site input less than the measuring voltage of standard voltage value; Measuring unit is used to measure the maintenance of described aerogenerator till from input test voltage to described aerogenerator off-grid and is incorporated into the power networks the time; Adjustment unit; be incorporated into the power networks the time less than the default threshold values time if be used for described maintenance; then adjust the switching time of crow bar holding circuit of described aerogenerator and/or the bypass resistance value of described crow bar holding circuit; and the under-voltage protection definite value of aerogenerator, make described maintenance be incorporated into the power networks the time more than or equal to the described threshold values time.
The measuring system that aerogenerator low-voltage maintenance of the present invention is incorporated into the power networks; can select the switching time of suitable crow bar holding circuit and the bypass resistance value of crow bar holding circuit for aerogenerator; and the under-voltage protection definite value of aerogenerator; make aerogenerator possess suitable low voltage ride-through capability thus, the safety of protection electrical network.
The professional should further recognize, the unit and the algorithm steps of each example of describing in conjunction with embodiment disclosed herein, can realize with electronic hardware, computer software or the combination of the two, for the interchangeability of hardware and software clearly is described, the composition and the step of each example described prevailingly according to function in the above description.These functions still are that software mode is carried out with hardware actually, depend on the application-specific and the design constraint of technical scheme.The professional and technical personnel can use distinct methods to realize described function to each specific should being used for, but this realization should not thought and exceeds scope of the present invention.
The method of describing in conjunction with embodiment disclosed herein or the step of algorithm can use the software module of hardware, processor execution, and perhaps the combination of the two is implemented.Software module can place the storage medium of any other form known in random access memory (RAM), internal memory, ROM (read-only memory) (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or the technical field.
Above-described embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is the specific embodiment of the present invention; and be not intended to limit the scope of the invention; within the spirit and principles in the present invention all, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.